1. Field of the Invention
The present invention relates generally to a low-temperature delivery system, and more particularly to a low-temperature delivery vehicle and the method of enhancing the freezing capacity thereof.
2. Description of the Related Art
Low temperature delivery trucks are the common equipment used in the low temperature delivery system to transport foods, medicine, chemical goods and so on. The conventional low temperature delivery truck has a container. The container is provided with an isolating layer on a wall thereof to form a chamber therein, such that it keeps the goods stored therein in a well condition. Some trucks are equipped with a refrigerator to provide the chamber in a low-temperature environment. Some refrigerators have an independent power and others are connected to the engine of the truck. Other truck is provided with no refrigerator but with cold blocks mounted on/in the wall of the chamber. The truck equipped with the refrigerator provides the chamber in a lower temperature for a longer time than that of the truck without the refrigerator. As a result, the truck equipped with the refrigerator is broadly used in long distance transportation or the goods having to be stored in a lower temperature environment.
The temperatures for storing various goods have to meet the properties of the goods. For example, milks are preferred to be stored in an environment about 4° C. and ice creams are preferred to be stored in an environment about −20° C. It is easy to understand that the truck has to be equipped with the refrigerator with greater power while the goods stored in the truck have to be stored in an ultra-freezing environment. But such refrigerator is much heavier and takes much space than the normal refrigerator, so that the cost is much higher to transport the goods, such as ice cream, which have to be stored in an ultra-freezing environment.